Abstract The proposed `HOME' project is in the NIH/OAR high research priority area of eradicating HIV from persistent reservoirs and responsive to the parent RFA for highly innovative studies at the nexus of substance abuse and HIV/AIDS. Most HIV anatomical reservoirs are hard to reach but studying blood alone is not enough to fully characterize HIV reservoirs. Thus, we will leverage prior NIH investments in our unique `Last Gift Cohort'. No such cohort is available elsewhere. The cohort obtains blood (before death) and a uniquely large set of tissues (within 6 hours after death) comprehensively from persons with HIV (PWH) who die while on documented, suppressive antiretroviral therapy (ART). For our HOME project, we will collect the following 17 tissues/fluids: blood, gut (ileum and colon), lymph nodes, kidney cortex, spleen, lungs, liver, genital tract (prostate/testes or cervix/ovaries), adipose tissues (abdominal, subscapular and pericardial), heart, brain (basal ganglia, frontal cortex and cerebrospinal fluid). We will then use these samples for state-of-the-art `Single-Cell Multi-Omics' technologies to address the following Goals, which are directly responsive to the parent RFA: ? Goal 1: To Deeply Characterize the HIV Reservoir (Size and Activity) in the Blood and Tissues at a Single Genome Level in Relation to Opioid Levels. ? Goal 2: To Deeply Characterize the T Cell and HIV DNA Clonality in the Blood and Tissues to ?Quantify the Distribution and Diversity of Clonal Expansion? in relation to opioid levels. ? Goal 3: To identify HIV and Opioid-associated immunologic Mechanisms Associated with HIV Persistence and Increased HIV RNA Transcription at the Single Cell Level. By leveraging our unique source of tissues and data generated through state-of-art methods, we will for the first time deliver a map of HIV persistence, activity and clonality across the human body in relation to opioid use. We will also reveal comprehensive molecular details and define parameters of HIV persistence at single-cell resolution, which will uniquely advance HIV cure efforts.